Reset Outlook View
Hi RaviMistry2,
Based on my test, the default view of Outlook is Compact, you could click View > Change View to change the view and see if the view of Outlook changes.

If it is still not changed, you could also try to reset view like below:
1. Exit Outlook client.
2. Right-click Start button and select Run, then type in "Outlook /cleanviews" in the Run box and press Enter key to launch Outlook.
Note: Before the above operation, please back up any customized view setting in advance.
If you have further concern, please capture screenshot about the "Change View" list for further understanding.
Kind Regards,
Betty
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